Re: Storage choice for Oracle database on VMware

Yes,
with "setall" iops and throughput are significantly higher.

I don't report the numbers because there are too many variables involved and I have to run some additional tests.

Regards
Dimitre

Il giorno lun 12 nov 2018, 00:47 Ls Cheng <exriscer_at_gmail.com> ha scritto:

> I guess for good? I am wondering because I have no experience with SETALL
> in XFS, only used in ext3 and ext4 and SETALL works very good.
>
> Thanks
>
>
> On Sun, Nov 11, 2018 at 9:27 PM Radoulov, Dimitre <cichomitiko_at_gmail.com>
> wrote:
>
>> Yes,
>> and in our environment it really makes a difference.
>>
>>
>> Regards
>> Dimitre
>>
>>
>>
>>
>>
>> Il giorno dom 11 nov 2018, 20:57 Ls Cheng <exriscer_at_gmail.com> ha
>> scritto:
>>
>>> Hi Radoulov
>>>
>>> Just wondering in youtr tests did you set FILESYSTEMIO_OPTIONS to
>>> SETALL in xfs?
>>>
>>> Thanks
>>>
>>>
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>>>
>>> On Fri, Nov 9, 2018 at 3:46 PM Radoulov, Dimitre <cichomitiko_at_gmail.com>
>>> wrote:
>>>
>>>> Hello all,
>>>>
>>>>
>>>> after a few quick tests on XFS and ASM (calibrate_io and swingbench) I
>>>> see that direct and asynchronous I/O definitely make a difference.
>>>>
>>>> Stefan and Neil, thank you for your suggestions!
>>>>
>>>>
>>>>
>>>> Regards
>>>>
>>>> Dimitre
>>>>
>>>>
>>>>
>>>> On 31/10/2018 12:29, Neil Chandler wrote:
>>>>
>>>> Radoulov,
>>>>
>>>> The caching in the SGA understands your data usage patterns through the
>>>> LRU algorithms and will have cached all of the best data. The FS cache, if
>>>> you dump it out, will look a lot more like white noise with few discernable
>>>> patterns. The SAN cache even more so. The more single block reads you have,
>>>> the more like white noise it all looks. The liklihood of there being a
>>>> cache hit in the FS or SAN cache is relatively low. The advantage of direct
>>>> path reads significantly outweights the advantage of both of those caches.
>>>> It is worth noting in that on most SAN caches, if you specify that the LUN
>>>> is for a database it will disable read-ahead to pre-populate the cache as
>>>> it understands that it is not the best use of the cache (the general rule
>>>> is that SAN cache should be reserved exclusively for writes when the SAN is
>>>> used for the database.)
>>>>
>>>> Note that these statements are generalisation, and that there may be
>>>> cases where your assertion is true but they will be an edge case and I
>>>> would recommend that you have a provable scenario to justify running in
>>>> that configuration.
>>>>
>>>> Neil Chandler
>>>> Database Guy.
>>>> ------------------------------
>>>> *From:* oracle-l-bounce_at_freelists.org <oracle-l-bounce_at_freelists.org>
>>>> <oracle-l-bounce_at_freelists.org> on behalf of Radoulov, Dimitre
>>>> <cichomitiko_at_gmail.com> <cichomitiko_at_gmail.com>
>>>> *Sent:* 31 October 2018 07:20
>>>> *To:* Andrew Kerber
>>>> *Cc:* lkaing_at_gmail.com; contact_at_soocs.de; Oracle-L Group
>>>> *Subject:* Re: Storage choice for Oracle database on VMware
>>>>
>>>> Thank you all for the valuable input!
>>>>
>>>> > what is the problem with direct I/O? You should never run an Oracle
>>>> database through page cache anyway :)
>>>>
>>>> I'm not sure if direct I/O is always the best choice. I think that
>>>> certain workloads may benefit from the FS cache.
>>>>
>>>> Anyway, I'm wondering why setall is still not the default value for
>>>> filesystemio_options on Linux (most probably because of the bugs with
>>>> certain filesystems and kernel versions).
>>>>
>>>>
>>>>
>>>> Regards
>>>> Dimitre
>>>>
>>>>
>>>> Il giorno mar 30 ott 2018, 22:38 Andrew Kerber <andrew.kerber_at_gmail.com>
>>>> ha scritto:
>>>>
>>>> Most places with growing databases and heavy duty environments on
>>>> vmware use ASM. Some use XFS or similar and LVM, though I am not fond of
>>>> those.
>>>>
>>>> On Tue, Oct 30, 2018 at 4:34 PM Leng <lkaing_at_gmail.com> wrote:
>>>>
>>>> Asm is great when you plan correctly. If you don’t it’s very painful.
>>>> Eg. If you have different sized disks asm will be forever rebalancing, and
>>>> failing as there is not enough space on the odd disk. So you need to vacate
>>>> the diskgroup to rebuild it. (Yes, you know... not my fault, the previous
>>>> consultant did it...) If there’s an asm bug you may have to take an outage
>>>> on the Asm to apply the patch.
>>>>
>>>> Normal disk operations like dd to asm is almost impossible. Trying to
>>>> find that corrupted data block on the asm disk takes great asm expertise
>>>> from a great oracle support engineer.
>>>>
>>>> Those were some up of my worst asm nightmares. It was only 2 years ago.
>>>> I have since moved on...
>>>>
>>>> Cheers,
>>>> Leng
>>>>
>>>> > On 31 Oct 2018, at 7:20 am, Stefan Koehler <contact_at_soocs.de> wrote:
>>>> >
>>>> > Hello Dimitre,
>>>> > what is the problem with direct I/O? You should never run an Oracle
>>>> database through page cache anyway :)
>>>> >
>>>> > I would go with tweaked XFS (e.g. "nobarrier" as this information is
>>>> usually not passed through correctly with VMDKs on VMFS, etc.) if it is
>>>> just one single instance in this VM.
>>>> >
>>>> > Best Regards
>>>> > Stefan Koehler
>>>> >
>>>> > Independent Oracle performance consultant and researcher
>>>> > Website: http://www.soocs.de
>>>> > Twitter: _at_OracleSK
>>>> >
>>>> >> "Radoulov, Dimitre" <cichomitiko_at_gmail.com> hat am 30. Oktober 2018
>>>> um 19:12 geschrieben:
>>>> >>
>>>> >> Thank you Chris, Matthew and Niall,
>>>> >>
>>>> >> so the question is if performancewise ASM is worth it.
>>>> >>
>>>> >> With the default Oracle database settings the I/O on XFS would be
>>>> synchronous, right?
>>>> >>
>>>> >> And if I understand correctly Note 1987437.1, on Linux you cannot
>>>> enable async I/O without turning on direct I/O too.
>>>> >>
>>>> >> Regards
>>>> >> Dimitre
>>>> > --
>>>> > http://www.freelists.org/webpage/oracle-l
>>>> >
>>>> >
>>>> --
>>>> http://www.freelists.org/webpage/oracle-l
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Andrew W. Kerber
>>>>
>>>> 'If at first you dont succeed, dont take up skydiving.'
>>>>
>>>>
>>>>
>>>
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>>

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